one official calls it a very active plot, led by osama bin laden's personal secretary. they have been tracking chatter, but in recent days one official said a lot started blinking red. so now look at the map. every embassy that's supposed to be open right now is shut, and right in the middle cairo. americans here keeping their heads down. >> keep as low a profile as i can. obviously i'm a sizable guy that looks like what i am, an american. and that said, i don't walk into harm's way intentionally. avoid large crowds where i can. >> meanwhile, president obama's top military advisor and chairman of the giants chiefs of staff, general martin dempsey, said the threats intercepted are significant and officials are taking the threats seriously. on" this week "he sat down in an exclusive interview with martha raditz. he said how a possible terrorist attack could be carried out, he said the threats appear to be far reaching. >> a significant threat strain and we are reacting to it. >> is the threat to blow up an embassy, consulate or something else? >> that part is unspecified